This probably just splits B+ tree pages. I suggested something similar for using sqlite with static web pages see [0]
Distributed search engines are not new, many companies tried to make them [1].
I think the main challenges of distributed search engines are not technical. I don't think there isn't much financial incentive to create/maintain/seed them.
There isn't much advantage to using them either (if a alternative is available). I think the only viable use case for them is for indexing pirated torrents.
Maybe a foundation could use this type of technology to lower their expenses. Like a charity version of Google